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    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        //default 默认  break 打破 case 情形 switch 开关
        switch (80) {
            case 90:
                console.log('A');
                break;
            case 80:
                console.log('B');
                break;
            case 70:
                console.log('C');
                break;
            default: 
                console.log('E');
        }
        console.log('game over');
    </script>
</body>

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